At 24 hours after clone induction, type I and II neuroblast clones in l(2)gl334/l(2)gl3644 larval brains contain a single neuroblast, as occurs in wild type. However, at 48 hours after clone induction, the mutant type I and II neuroblast clones contain supernumerary neuroblasts.
Intermediate neural progenitor cell derived clones in l(2)gl334/l(2)gl3644 larval brains contain multiple supernumerary type II neuroblasts.
l(2)gl334/l(2)gl3644 larval brains contain an increased number of type II neuroblasts and intermediate neural progenitor cells compared to wild type.
Mutants show an increased number of brain neuroblasts at 96 hours after larval hatching compared to controls. Mutant neuroblast clones in the larval brain often contain two neuroblasts, and can contain up to six neuroblasts, in contrast to control clones which contain a single neuroblast.
l(2)gl4/l(2)gl334 L3 larval brains are larger in volume (65% larger) than l(2)gl334/+ brains. l(2)gl334/l(2)gl334 L3 larval brains possess 136 +/- 12 neuroblasts compared to a l(2)gl334/+ value of 92 +/- 6. Homozygous l(2)gl334 L3 larval imaginal discs are enlarged compared to l(2)gl334 heterozygous discs. They don't exhibit a monolayer at L2/L3 larval stages and have a ~49% increase in the number of neuroblasts compared to controls. l(2)gl334 mutant third instar leg and wing imaginal discs are highly enlarged and disorganised, and often fuse with each other or nearby tissues. At the cellular level, mutant epithelial cells are round instead of columnar, with an expanded apical membrane domain.
Salivary glands isolated from 8 day old third instar l(2)gl334/l(2)gl4 larvae and maintained in Schneider culture medium for 24 hours are considerably reduced in size compared to wild-type controls and have a "bunch of grapes" shape. The cells of the mutant glands are nearly spherical in form with a reduced surface of cell-to-cell contact. Administration of 10[-5]M 20-hydroxyecdysone fails to induce the histolysis of the mutant glands. No sign of vacuolisation or abnormal pattern of organelle distribution can be detected in treated mutant salivary gland cells and the overall organisation of the glands and structure of the cells is similar to those of untreated mutant glands.
l(2)gl558/l(2)gl334 transheterozygotes show temperature-sensitive viability. The temperature-sensitive period is biphasic; the first phase is embryonic and the second phase is in the third larval-prepupal stage.
Some Df(2L)U558/l(2)gl334 flies are viable. The viability is affected by temperature; the temperature sensitive period is diphasic at 17oC and 29oC.
18.4% of mutants die as larvae, 81.6% as pupae. Weak allele: brain and discs are small and rudimentary and grow slowly in transplants.